Articular fractures, and more particularly proximal humeral fractures, are a frequent event often seen in elderly patients, and comprise about 5% of all fractures. Although many proximal humeral fractures are stable injuries which can be treated non-operatively, surgical intervention is required in about 20% of all cases, particularly with complex fractures. However, complex fractures of the proximal humerus are notoriously difficult to manage, particularly in elderly patients. Indeed, internal fixation is difficult because of the small size of the bone fragments and the quality of the bone stock is often poor due to osteoporosis. In addition to these mechanical problems, there further is a risk of avascular necrosis of the humeral head (caput humeri).
Various devices and systems for proximal humeral fracture fixation are known in the art, including locking plates, intramedullary rods, and the so-called Bilboquet device.
Locking plates such as proximal humeral fixation plates are typically made from stainless steel or titanium, and are locked onto the bone via screws, thereby providing stability. However, especially in case of osteoporotic bone, the relatively long screws, situated in the subchondral plate to enhance stability may perforate the caput humeri completely, and cause damage to the glenoid cavity. Moreover, locking plates may provide for fixation, but do not provide for sufficient stability in all cases. This is particularly problematic in proximal humeral fractures with a varus deformity or metaphysial comminution.
Implants such as intramedullary rods share the load with the bone, rather than entirely supporting the bone. However, these implants may cause enlargement of the fracture and/or iatrogenic complications in the subacromial space. Moreover, the possibilities for fixation of complex fractures are limited.
The Bilboquet device (described in patent FR2669528) is a two-part implant consisting of a circular staple which is impacted into the articular surface of the caput humeri, and a diaphyseal stem that inserts into a cup provided onto the staple. However, the position of the staple in the caput humeri is difficult to adjust during surgery, and the implantation of the device into the bone requires an expansion of the fracture. Moreover, the limited number of implant models limits the amount possibilities for the surgeon. Similar problems occur with other articular fractures.
There is therefore a need for methods and systems for fixation of complex articular fractures which mitigate at least one of the problems stated above.